


Alliance

by Marks



Category: Haikyuu!!
Genre: Aged-Up Character(s), Alternate Universe, Alternate Universe - Royalty, Arranged Marriage, First Times, Hand Jobs, M/M, Oral Sex, SASO 2017, Sappy
Language: English
Status: Completed
Published: 2017-06-03
Updated: 2017-06-03
Packaged: 2018-11-08 15:26:46
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,080
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11084466
Author URL: https://archiveofourown.org/users/Marks/pseuds/Marks
Summary: Keiknowsthey have a boy his age. How could he forget? Prince Tadashi's a crown prince like Akiteru, and their parents want them to getmarriedsomeday to form a stupidalliance. "Tch," Kei mutters under his breath. He's not a bargaining chip. He's Tsukishima Kei, second-in-line to the royal throne, and he's not going to let this happen.





	Alliance

**Author's Note:**

> For SASO 2017, Bonus Round 1, Alternate Universes!
> 
> princessid prompted: "Yamaguchi Tadashi/Tsukishima Kei - this is the most self-indulgent thing i have ever prompted, arranged marriage au (they are both princes!! they must unite their nations for important plot reason x that doesn't really matter! how will they get past the awkwardness and grow close?!!? i'm dying!)"
> 
> I'm glad princessid specified self-indulgence because OH GOD IS THIS EVER SELF-INDULGENT. AND SAPPY! SO SAPPY! Did you know that SASO fills only have to be more than 400 words? Haha good job, me.

Kei is ten years old and grumpy. His brother would laugh and say that was just normal, but Akiteru is stupid. He's also crown prince of the Kingdom of Tsukishima and Kei's favorite person in the world, but that's beside the point. Kei isn't _always_ grumpy. But he is right now.

"They have a boy your age," Kei's mother, the queen, reminds him. She waves at her subjects lining the road as they go past. "Don't look so sad. This is too long a trip for you to pout the whole way, and then your face will freeze like that."

Kei _knows_ they have a boy his age. How could he forget? Prince Tadashi's a crown prince like Akiteru, and their parents want them to get _married_ someday to form a stupid _alliance_. "Tch," Kei mutters under his breath. He's not a bargaining chip. He's Tsukishima Kei, second-in-line to the royal throne, and he's not going to let this happen.

*

"Whoa!" Prince Tadashi exclaims as Kei straightens up after dusting off his boots. "You're so tall! I thought you were my age."

"I am," Kei says defensively. He pushes up his glasses and crosses his arms over his chest as he waits for Tadashi to call him a freak. Tadashi doesn't even come up to his shoulders.

"That's so _cool_!" The crown prince of Yamaguchi goes up onto his tiptoes and brings a hand from the top of his head to the top of Kei's and back. "Awesome," he concludes, balling his hands up into fists. His eyes are lit up like stars and he looks so excited that Kei can hardly look at him. "What do you eat? Lots of stuff, I bet."

Kei shrugs. "No. Regular food, I guess. Everyone says I don't eat enough."

" _Really_?" Tadashi says, and shakes his head, impressed, like Kei just gave him the secret to life itself. He feels his face heating up under the excited scrutiny, but it's not that bad. "Then I guess you're just awesome. Come on, I'll show you my rooms!" He grabs Kei by the wrist and even though Kei usually hates when people touch him without asking, he lets himself be dragged along. Doesn't mind it. Kind of likes it, maybe.

*

"You know, Kei, we'd never do something you didn't want," his mother says on their way home a few days later. "Alliances aren't everything. I rejected the first choice my parents made for me because I liked your father more. After all, I was going to be queen some day and I should have some say over what happens in my own life. And now you're second-in-line."

Kei looks over at her, surprised, but she's staring straight ahead. Kei thinks about the last few days, how easy it had been to talk to Prince Tadashi, how quickly the days passed in his company. Kei guesses it wasn't too annoying.

"No," he says eventually. "It's all right."

*

Kei is twenty years old and grumpy.

"I don't see why I have to be nice to them," he says.

Akiteru laughs and thumps him on the back. "Because they're _family_."

"By marriage," Kei reminds him, adjusting his glasses. _He_ isn't the one who married a Tanaka. They aren't even a high-ranking family, and they're all so loud. Kei's had time to get used to Princess Saeko in the two years she's lived with them, likes her most of the time even, though he'd never admit that out loud. It's mostly just her younger brother and all his friends, the stupid ones who act so familiar with him.

"Yes, and they're here for _your_ wedding," Akiteru says. His voice chokes on the last word and he sniffles a little.

Kei groans. "Don't you start," he warns.

"What?" Akiteru reaches into his coat and pulls out a handkerchief to dab at his eyes. "Can't a man be sad that his baby brother is growing up and leaving him?"

"I'll visit often," Kei grumbles, folding his hands in front of him. "I'm getting married, not dying." He grunts when Akiteru launches himself at him for a very teary hug.

*

The ceremony is well-attended. Kei still feels uncomfortable in formal attire, even though he's had his whole life to get used to it. And it's not the starched shirt or embroidered overcoat that are making him itchy. Sure, he'd liked Prince Tadashi well-enough when they were ten, but that's a dim memory now and a whole decade has passed since they'd last seen one another. Maybe they wouldn't get along. Maybe Tadashi grew up ugly. Maybe he'd think Kei was a jerk for even thinking that. Maybe Tadashi doesn't like men the way Kei does, so they'll just be a political alliance in a sham marriage. Kei thinks the last one might be tolerable, as long as they can be cordial to one another. The royal family beams at him from the front row; Kei is ready to do his familial duty.

He straightens his shoulders when Tadashi's retinue is announced. A whole parade of people are ushered in and seated. He recognizes Tadashi's parents and shifts from one foot to the other. _Hurry up. We don't have all day,_ Kei thinks, even though they do. Then fanfare plays and a nervous-looking young man appears in the entranceway.

"Crown Prince Yamaguchi Tadashi," a bored man announces as Tadashi begins to descend the stairs toward the crowd. Kei's eyes widen. 

Well. 

He certainly hasn't grown up ugly.

*

"You must be exhausted," Tadashi says, hours later, after the ceremony and the banquet held in their honor. Kei is trying to get comfortable in their carriage and it's not working; they've been on the road for over an hour now and he always has trouble in these because he's so tall.

They've barely even talked since Tadashi's arrival. Kei's never been very good at initiating conversation, despite his brother constantly berating him to improve his social skills, and every time Tadashi opened his mouth at the banquet table, someone else would approach to offer congratulations or pull one of them away for a talk. Then they'd been loaded up into a carriage for an overnight trip to an inn on the way to Tadashi's homeland, and the footman actually _winked_ at Kei as he climbed inside. Kei shudders at the memory.

" _I'm_ exhausted," Tadashi admits. He laughs. "It's been a very strange day." His voice isn't deep, but it's sweet and pleasant to listen to. Kei wonders what a lifetime of hearing it will be like.

"Yes," Kei says cautiously. "Very stra—"

His words are cut off when Tadashi launches himself across the carriage, mouth-first. It's not even a kiss, really, because Kei's mouth is open and Tadashi barely even touches his lips. Their teeth clack together and Tadashi's on the other side of the carriage again before Kei's even registered what's happened.

"Sorry!" Tadashi says, burying his face into his hands. "I don't know what I'm doing."

Kei blinks and draws his eyebrows together. So this is his husband. He sighs, irritated. "And what makes you think that I do?"

Tadashi looks up again. "Because I have _eyes_ ," he says incredulously. 

"What's _that_ supposed to mean?" Kei feels a bubble of anger start to rise up.

"You're just so handsome!" Tadashi blurts out. The bubble pops. "I remember you when we were kids and you were so tall and cool then, and then you turn out like – like this." He gestures wildly and nonspecifically. "You can't tell me you haven't had opportunities."

Of course he has. Kei has had lots of people, both men and women, throwing himself at him since he was a teenager. He's a prince, after all, and Kei understands that people are attracted to power. But. 

"I've been betrothed since I was ten years old, you know."

Tadashi widens his eyes as he takes in Kei's meaning. Then he slumps in his carriage seat and grins. "You're not as scary as you look at first, are you?"

The carriage slows to a stop and Tadashi climbs out before Kei can ask what he'd meant by that.

*

The proprietors of the inn flutter all around them, clearly nervous to have important guests. Kei doesn't understand why; the accommodations are perfectly adequate, but he's glad when everyone finally goes away.

Glad, that is, until he realizes that he's alone with Tadashi for the first time since they were just children. And that they're married. The room glows with dozens of candles and there's a large bed in the middle of the room. Someone's sprinkled flower petals all over the blankets, an attempt at romance, Kei supposes, but it seems wasteful to him. 

"Hmm," Kei says. He's not nervous, or at least that's what he tells himself. It's not – Kei's not unaware of what's expected of him, he's read about it plenty, and he's not uninterested. But Kei doesn't like looking foolish; he thinks of the way Tadashi launched himself at him in the carriage and wonders if he'll do that again. 

"We don't have to—I mean, if you're tired." 

Kei looks over his shoulder at Tadashi, who's nervously wringing his hands.

"There will be other nights!" Tadashi says brightly, but even though they haven't spent a lot of time together, Kei thinks it's fake brightness. He doesn't like it.

"Do you want to wait for another night?" Kei says, turning around. 

Tadashi scratches his head. "Ah, what a loaded question."

"And that wasn't an answer." 

Kei steps closer to the bed; he doesn't sit, but he does finally shrug off his uncomfortable coat, folding it over a nearby chair, and undoes the top two fastenings of his scratchy shirt. He doesn't miss that Tadashi watches his hands while they're near his throat, but he finds he doesn't mind it. Then Tadashi gets a determined look on his face and strides across the room; Kei can see his royal upbringing here now, and he wonders if it's a mask Tadashi wears to get through things or just something natural about him that needs to be encouraged. He hopes it's not a mask; it's a good look for him. 

Tadashi puts one hand on Kei's waist, another on the side of his face; Kei remembers how he'd towered over Tadashi when they were small, but it seems the years have been kind to him. He's still shorter than Kei, but not by much, and Kei is taller than almost everyone. "You're right," he says, "that wasn't an answer. I don't want to wait for another night."

Kei's shoulders don't sag in relief. He's been too carefully taught for that, but he does allow it when Tadashi angles his head up and leans toward Kei. This definitely counts as a kiss, a soft press of lips that still feels a bit awkward until Kei tilts his head a bit. Then Kei's head starts to swim and his stomach swoops and Tadashi opens his mouth just enough that Kei finds himself doing the same to keep them connected. Feeling Tadashi's tongue against his brings on another shock, one that makes him grab two handfuls of Tadashi's shirt. When they break apart, Tadashi's chest rises and falls rapidly.

"We should sit," Kei says logically because the bed is right there and standing around is foolish under those circumstances, not because Kei's knees feel like they're made of water. He perches himself on the edge of the bed and waits for Tadashi to follow suit.

"Just sit?" Tadashi asks, and it sounds innocent coming from his mouth, even though his smile is sly. 

"Are you _sure_ you've never done this before?" Kei says, and he means it to sound like a joke but instead it sounds like he's suddenly out of his depth.

Tadashi shrugs. "Not unless my right hand counts," he says, and Kei's eyes widen at his boldness. "Was that too much information?"

Kei shakes his head and swallows. "We're married now," he says, out loud, rolling the words around in his mouth, just to see what they feel like. "I suppose that makes me your new right hand."

Tadashi laughs, then ducks his head. "I wouldn't mind that," he says seriously. He puts one knee up on the bed, right alongside where Kei sits. Kei finds himself lifting his chin without thinking, and Tadashi meets him in the middle. This time, their mouths open easily and Kei feels himself being pushed back against the pillows as Tadashi climbs onto the bed, climbs on top of _him_. Kei tries pushing Tadashi's coat off his shoulders, but his arms get all tangled and they're still kissing while Tadashi struggles like a fish in a net.

"Wait, wait," Tadashi says, breaking away, breathless. "We should have done this part first." He sits back and starts peeling away the layers of his wedding clothing, just letting them pool onto the floor.

"Forward," Kei mutters, but he doesn't look away as Tadashi pulls off thing after thing.

"Is this – should I not –?"

"It's fine."

Tadashi nods. "Then don't let me be alone in this."

Kei's face goes hot, but he nods. He sits up and mirrors what Tadashi had done, refusing to look anywhere but the walls, focusing on the way the candlelight makes dancing shadows. Tadashi slides over and helps him, eager, pushing Kei's clothing off the side of the bed and running his hands up Kei's thighs. The movement makes Kei shiver.

"I think we're doing pretty well," Tadashi says, once all of Kei's clothes are gone, too. Kei doesn't say anything, just bites his lip and won't look anywhere but Tadashi's face.

All right, fine. He is nervous. He can even admit that to himself now.

Tadashi kisses him again and pulls him down so they're stretched out next to one another. It's odd, but it already feels familiar enough that it relaxes him a little. Kei closes his eyes and shivers again when he feels Tadashi's hand on his bare hip, but he doesn't pull away, not when Tadashi runs his hand up his side, not when Tadashi breaks away to press a tentative kiss on the side of Kei's neck, not when he feels himself stretching to chase Tadashi's mouth again, the next kiss deeper and wetter than before. Everything starts to feel good instead of strange, and he runs his hand down Tadashi's chest, his stomach; Tadashi moans against his mouth as Kei's hand dips lower and the sound is so startling that Kei's hips stutter forward on their own.

He opens his eyes then, breaking another kiss to finally dare a glance below Tadashi's neck. He wants to see if – if Tadashi's also getting as much out of this as Kei is. The freckles on Tadashi's cheeks don't stop there, sweeping across his shoulders and down his chest before fading out lower down. It's an attractive effect. And Tadashi is hard, he's so _obviously_ hard from the kissing and touching, at least as hard as Kei himself is and it's so much of a relief that Kei finds himself smiling.

"What?" Tadashi says, looking panicked.

"Nothing," Kei says, and reaches out to wrap his fingers around Tadashi's cock. Tadashi moans, loud and sudden, and Kei thinks of those poor fluttering innkeepers just outside their room. But he has a rose petal stuck to his wrist, so they probably knew what they were getting into. "Hmm," he says to himself as he strokes, trying to find a good angle. 

"Are you always so methodical?" Tadashi gasps. Kei rubs his thumb over the head, and a drop of precome sticks to the pad of his finger.

"Not always." Kei lets go of Tadashi and licks his thumb. He can see the interested way Tadashi watches as his tongue darts out of his mouth, so he does it again. Tadashi gulps. Kei pushes him back on the bed and starts to mouth a line down Tadashi's body. "I hope this is all right, I've only read about it in books." He pauses at Tadashi's nipple, licking first, then biting down and making him gasp, continuing down his chest and stomach, dipping his tongue into Tadashi's navel. Tadashi moans the whole way, and Kei takes note at all the places Tadashi jerks beneath him.

He stops when he reaches Tadashi's dick, mouth hovering just over it. Kei's a whole jumble of emotions then – he's tired from the day, and concerned about how much Tadashi will like this; he's so turned on himself, and he just wants to be good at everything. He wants to be a good husband and a good leader. Also, his mouth is watering a little, just from his proximity to Tadashi's dick, which is disconcerting but doesn't stop him from licking a line up, just like he had on his thumb moments ago. Tadashi pants and whimpers when Kei opens his mouth to take in as much of him as he can without gagging. It isn't a lot, so he's relieved when Tadashi uses his own hand to help Kei out. Every time he slides his mouth down, feeling Tadashi's dick heavy on his tongue, his lips meet Tadashi's fist and together they work him over like that, Kei following Tadashi's lead with his hands on Tadashi's thighs, digging in his fingertips and grinding his own hips into the bed. 

When he comes, Tadashi tries warning Kei at first, babbling his name in an attempt to get him to pull off, but when Kei makes it obvious he's not going anywhere, Tadashi gives up and just starts saying, "Kei, please, Kei, Kei, _Kei_ ," until he's coming on Kei's tongue and down his throat.

Kei sits back on his heels and waits as Tadashi's breathing evens out again. He's still painfully turned on, and the taste of Tadashi in his mouth isn't nearly as unpleasant as he'd been made to believe. He already wants to do it again — better, more, or other things – whatever Tadashi wants, Kei wants to give it to him.

"You learned that from a book?" Tadashi says, once he can speak in full sentences again.

Kei shrugs. "Tadashi," he says, and it comes out sounding far more breathless than he intended, a reminder of his own predicament. He starts to take himself in hand, but Tadashi's already scrambling to sit up, his own mouth on Kei's at the same moment his hand wraps around Kei's dick. Kei doesn't move his own hand, so they jack him together, Kei showing his husband exactly what he likes, all the practice with _his_ right hand that he'd had over the years paying off. It's good, but he just wishes things were a little wetter; Kei comes in spurts over both their hands picturing Tadashi's pretty mouth stretched around him.

After, Kei's limbs are heavy, and his eyelids are heavy. He only just manages to clean himself up, help Tadashi blow out the candles in the room, and remove his glasses before he's sinking gratefully into the mattress.

"Consummated," Kei mumbles, just as he's drifting off.

Tadashi finds his hand underneath the blanket and links their fingers together. "What?" He squeezes Kei's hand.

"We've consummated," Kei repeats. "Now we're official."

"Good," Tadashi says sleepily and yawns. "When I was a kid, and my parents started talking about alliances, you were the only person I met who ever felt right. You still feel right."

"Oh," Kei says, his heart thumping in his chest. It takes him a moment to realize he's happy.

*

Kei has lived in Yamaguchi kingdom for a little over two months now. He doesn't quite think of it as home yet, but he's getting there. He stretches out in bed, the bed he insisted he share with his husband and is disappointed, but unsurprised, to realize that he's alone.

Tadashi is very busy, of course; he's going to be king one day and his own father has already trusted him with many responsibilities. And Tadashi put Kei to work, too. When they first arrived at the castle after their wedding, Tadashi had asked him what he'd done for his own family. "Tactical analysis, mostly," Kei had said because he was good at seeing the big picture and even better at seeing fine details, and Tadashi's eyes had lit up and said he could definitely work with that. 

Which isn't to say they never make one-on-one time for each other.

Kei swallows, thinking about all that time, the way Tadashi will crowd him into an alcove or Kei will push Tadashi up against a wall, or how they'll take their leave from dinner too early to be respectable. Just a few hours earlier, Kei found himself unable to sleep in the middle of the night, and he supposes the restlessness woke Tadashi up, too. His cheeks grow hot at the memory of them reaching for one another almost thoughtlessly, of getting in between Tadashi's thighs, of Tadashi hot and tight around him and gasping Kei's name. Embarrassing. Kei's getting hard again just thinking about it.

There's sudden noise outside his chambers, three or so women talking, not realizing Kei's still in bed inside. "Who's on laundry duty today?" one asks, and the others all groan. "They're newlyweds," the same person reminds them.

"They'll slow down eventually, right?" a second voice asks. "I keep catching them in precarious situations in dusty corners and having to escape unseen."

"I can't really blame Prince Tadashi for being insatiable. The new prince is fine-looking," another says, "but he's a bit reserved, isn't he?" 

"Not in private, judging by his bedding." They all giggle and Kei sits up.

"I think it's sweet," the first voice says. "It's nice it turned out to be a love match. Prince Tadashi deserves that, don't you think?"

 _Love match_ , Kei thinks, his heart squeezing in his chest. 

"He never used to smile this much," the voice goes on. "But that's what it's like, being in love."

In love. Is that what this is? Kei never gave himself a second to think beyond responsibility, about the alliance between their lands, about how this had been the plan all along. He wanted to give himself a comfortable life, some modicum of happiness even, perhaps. He'd never considered –

Kei thinks about how warm he feels when he's around Tadashi, how he misses him when they're apart, and how it feels like a hundred butterflies have suddenly woken up in his stomach whenever Tadashi reappears. He touches his own face, and thinks about how he never really smiles, but how he already is just then.

*

Tadashi comes in while Kei's working, smiling as he takes in Kei's maps and stacks of neatly written notes, the way Kei reaches under his glasses to rub at his tired eyes. "Your brother sent a messenger," he says.

"Akiteru?" Kei stands up. "Is everything all right?"

"Yes," Tadashi says, "but you may want to plan a visit soon. It seems you'll soon be third-in-line for the throne."

Kei blinks, taking in Tadashi's meaning. "Oh," he says, finally. He sighs. "Akiteru will cry even more than he does now."

Tadashi slides his arms around Kei's waist and buries his face in his neck; Kei can feel it when Tadashi's chest expands as he breathes him in, and it makes his face heat up. He wonders if they can do anything in here without messing up Kei's hard work, and wonders if he even cares if they do. Kei slides his fingers into Tadashi's hair and presses his fingers against Tadashi's scalp.

"You're not disappointed?" Tadashi mumbles into Kei's chest.

"Disappointed? With what?"

"You'll probably never rule your family's kingdom," Tadashi says.

Kei wrinkles his forehead. "I never wanted that." Why would he want that? He would, if duty demanded it, but for Kei to be king, his mother and Akiteru would both have to die. What sane person would want that? Besides... "I'm part of your kingdom now."

He can feel it when Tadashi smiles against him. His husband lifts his head, and his smile is still there, still radiant. Kei lets himself be kissed and kisses back, letting the warmth he feels whenever he and Tadashi touch wash over him again and again. It's already happened so often, but Kei doesn't think he'll ever get used to it.

"I'm happy here. This is where I belong," Kei says, and he realizes it's the truth. "I belong here with you."


End file.
